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18" rims.
07-09-2014, 06:23 AM
Post: #1
18" rims.
I thought this would look pants but actually.......

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07-09-2014, 07:04 AM (This post was last modified: 07-09-2014 07:05 AM by leonbray.)
Post: #2
RE: 18" rims.
looks a lot better than the 13" wheels. Might even force them to put more suspension in the car

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07-09-2014, 07:48 AM (This post was last modified: 07-09-2014 06:03 PM by Neonzapper.)
Post: #3
RE: 18" rims.
(07-09-2014 07:04 AM)leonbray Wrote:  looks a lot better than the 13" wheels. Might even force them to put more suspension in the car
Yes. Charlie Whiting is already making waves about all team suspension (especially Mercedes) being too loose now.

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07-09-2014, 06:30 PM
Post: #4
RE: 18" rims.
Why not, looks good.

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07-10-2014, 07:15 AM (This post was last modified: 07-10-2014 07:16 AM by Miguel.)
Post: #5
RE: 18" rims.
so there's less air inside an 18" tire than inside a 13 one!? counter intuitive!
http://joesaward.wordpress.com/2014/07/1...formula-1/

This is one rule change I would be looking forward to!

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07-10-2014, 08:01 AM
Post: #6
RE: 18" rims.
(07-10-2014 07:15 AM)Miguel Wrote:  so there's less air inside an 18" tire than inside a 13 one!? counter intuitive!
http://joesaward.wordpress.com/2014/07/1...formula-1/

This is one rule change I would be looking forward to!
Yes, less air and higher air pressure. I'm no Tech-Talk Tim, but I think it is because air generates heat which expands the (higher sidewall) 13 inch tire more like a balloon. With a smaller sidewall, the air pressure is higher, causing the tire to be stiffer on the sides, but pushing outward on the grip (tread or slick) surface.

I realize Joe is the expert here, but I believe both diameter tires revolve at the same rate of speed, however a smaller diameter tire covers the perimeter (road surface) more often than the larger perimeter tire. So, it would seem that a larger diameter tire would add tire life and use less fuel (lighter load and less fuel conservation during a race) to travel distance.

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07-10-2014, 08:31 AM (This post was last modified: 07-10-2014 08:41 AM by Miguel.)
Post: #7
RE: 18" rims.
(07-10-2014 08:01 AM)Neonzapper Wrote:  I realize Joe is the expert here, but I believe both diameter tires revolve at the same rate of speed, however a smaller diameter tire covers the perimeter (road surface) more often than the larger perimeter tire.

same angular velocity but the larger tire has a higher linear speed I guess

time to refresh high school physics
https://www.inkling.com/read/college-phy...nd-angular
Angular Velocity

How fast is an object rotating? We define angular velocity ω as the rate of change of an angle. In symbols, this is

(6.6)

where an angular rotation Δθ takes place in a time Δt. The greater the rotation angle in a given amount of time, the greater the angular velocity. The units for angular velocity are radians per second (rad/s).

Angular velocity ω is analogous to linear velocity v. To get the precise relationship between angular and linear velocity, we again consider a pit on the rotating CD. This pit moves an arc length Δs in a time Δt, and so it has a linear velocity

(6.7)

From we see that Δs = rΔθ. Substituting this into the expression for v gives

(6.8)

We write this relationship in two different ways and gain two different insights:

(6.9)

The first relationship in states that the linear velocity v is proportional to the distance from the center of rotation, thus, it is largest for a point on the rim (largest r), as you might expect. We can also call this linear speed v of a point on the rim the tangential speed. The second relationship in can be illustrated by considering the tire of a moving car. Note that the speed of a point on the rim of the tire is the same as the speed v of the car. See Figure 6.5. So the faster the car moves, the faster the tire spins—large v means a large ω, because v = rω. Similarly, a larger-radius tire rotating at the same angular velocity (ω) will produce a greater linear speed (v) for the car.
Figure 6.5 A car moving at a velocity v to the right has a tire rotating with an angular velocity ω…
Example 6.1
How Fast Does a Car Tire Spin?

Both ω and v have directions (hence they are angular and linear velocities, respectively). Angular velocity has only two directions with respect to the axis of rotation—it is either clockwise or counterclockwise. Linear velocity is tangent to the path, as illustrated in Figure 6.6.

and more in line with the tire size issue
http://mathcentral.uregina.ca/QQ/databas.../ben2.html

Here's something really interesting: Because the angular velocity depends on the circumference (and by implication, the radius), you can have something two things travelling at the same angular velocity, but different linear velocities.

Let's think of the (front) sprocket set on your bike. If you change from a small sprocket to a large sprocket, and keep your legs moving around the same number of rotations per minute (the same angular velocity), then you will go faster. That's because the linear velocity of the chain is what is driving the speed of the bike. So when you changed gears, you moved from a small radius sprocket (and therefore a small circumference) to a large radius (circumference) sprocket. When you multiply these two by the same angular velocity, you get a larger linear velocity with the large sprocket!

So large sprocket with twice the radius of a small sprocket should make you cover twice the distance in the same number of rotations of your legs.

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07-10-2014, 10:45 AM
Post: #8
RE: 18" rims.
(07-10-2014 07:15 AM)Miguel Wrote:  so there's less air inside an 18" tire than inside a 13 one!? counter intuitive!
http://joesaward.wordpress.com/2014/07/1...formula-1/

This is one rule change I would be looking forward to!

There is if the two wheels have similar overall diameters so the bigger wheel would need a lower sidewall on the tyre. Less of the wheel/tyre combination is given over to tyre as it were on the 18" option so there'll be less air.
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07-10-2014, 11:42 AM
Post: #9
RE: 18" rims.
(07-10-2014 07:15 AM)Miguel Wrote:  so there's less air inside an 18" tire than inside a 13 one!? counter intuitive!
http://joesaward.wordpress.com/2014/07/1...formula-1/

This is one rule change I would be looking forward to!

It's the rim size, not the tyre size.

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07-11-2014, 06:21 AM
Post: #10
RE: 18" rims.
(07-10-2014 11:42 AM)Yaaay Wrote:  It's the rim size, not the tyre size.

Indeed. Depending on the tyre outer radius and profile you could have virtually any air volume you like in a tyre on a rim of any diameter (but the same width).

If you see what I mean...

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07-13-2014, 05:46 PM
Post: #11
RE: 18" rims.
Lotus ran a car fitted with 18-inch wheels during the Silverstone Formula 1 test yesterday, in what could be the first step in a move to low-profile tyres as early as 2016.

Such a move would largely be for cosmetic and commercial reasons because 13-inch wheel-rims as currently used in F1 are largely used only in the budget end of the production car market.

The regulations mandating 13-inch rims in F1 are a legacy of a rule introduced to prevent teams fitting larger-diameter wheels to allow bigger brake discs. As brake disc size is now regulated, this is no longer a concern.

The overall size of the 18-inch tyre tested by Lotus yesterday remains the same, which means that the sidewalls were significantly lower.

Pirelli would like to bring in slightly larger wheels of 19/20 inches with even lower-profile tyres, although there is a limitation to how far you can go.

"For integrity reasons you still want a relatively tall sidewall," said Pirelli motorsport director Paul Hembery.

"Such are the lateral loads being passed from the tread into the wheel via the sidewalls, that geometry of very short sidewalls will make them want to pull off the rim in turns."

SUSPENSION

If the sport chooses to go in this direction it will have a big impact technically.

From onboard shots, we can see the tyre accounts for a large proportion of the car's suspension travel.

Going for a lower profile tyre will mean the car's suspension will have to account for the lost tyre compliance. This means it will have to be softer, with longer travel.

But the flipside of this is that currently the teams have no control over the compliance of the tyres, so larger wheels will give more influence over a car's total suspension compliance.

BRAKES

Currently, the brake discs and ducts fill the inside of the wheel with only tiny amount of clearance and the FIA is unlikely to want to allow larger brakes even though larger wheel rims could accommodate them.

But allow brake duct bodywork to fill the larger wheel is likely to create more aerodynamic performance from the car.

Either, larger discs and smaller calipers could be regulated to fill the wheels for a similar braking performance, or the current disc and duct size could be retained.

Teams also use the close proximity of the wheel and brake to tune the heat transfer from the carbon discs to the tyres through the wheel. With a large gap this tuning option will be lost.

These effects mean that teams will need significant notice ahead of the introduction of the new tyres, given the work that will need to be done on suspension, aerodynamics and brakes.


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07-15-2014, 12:12 AM (This post was last modified: 07-15-2014 12:12 AM by Neonzapper.)
Post: #12
RE: 18" rims.



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07-15-2014, 07:02 AM
Post: #13
RE: 18" rims.
I'm sold

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